The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Current sensors for detecting electric current include a shunt resistance type current sensor, a current transformer (CT), a Hall effect current sensor, and the like.
Among these current sensors, the shunt resistance type current sensor has been widely used due to its high accuracy and low price. The shunt resistance type current sensor has a shunt resistor, which is a resistor with low resistance, in a circuit to measure electric current and is configured to measure a current value based on a voltage difference between opposite ends of the shunt resistor.
A shunt resistance type current sensor in the related art includes an input bus bar connected to a power source, an output bus bar connected to a load, and a shunt resistor connected between the input bus bar and the output bus bar.
An inverter is connected to the power source, and the input bus bar is connected to a power module of the inverter. The shunt resistor is coupled to the input bus bar and the output bus bar through brazing and sensing wires are welded to respective opposite ends of the shunt resistor. The sensing wires have a connector coupled to a gate board of the inverter. The shunt resistor may be electrically connected to a current sensing circuit of the gate board by connecting the connector to the current sensing circuit of the gate board.
When electric current supplied from the power source through the input bus bar flows through the shunt resistor, a voltage value may be varied depending on the resistance of the shunt resistor, and thus the electric current flowing through the bus bars may be sensed.
However, since the shunt resistance type current sensor in the related art has a structure in which the shunt resistor is connected between the input bus bar and the output bus bar through brazing and the sensing wires are welded to the opposite ends of the shunt resistor, an assembly process of the current sensor may be complex, which results in an increase in manufacturing cost.
Furthermore, the shunt resistance type current sensor in the related art is difficult to be reworked since the shunt resistor and the sensing wires are mounted through brazing and welding.
In addition, in the shunt resistance type current sensor of the related art, separation or movement of the connector may cause deterioration in measurement quality since the current sensor is connected to the gate board of the inverter through the connector.